Device adapted to loudspeakers, telephones, or relays



May 3, 1938. F. WEITKOWITZ 2,116,293

DEVICE ADAPTED T0 LOUDSPEAKERS, TELEPHONES, OR RELAYS Filed July 11, 1933 2 Sheets-Sheet l /nvent0r: Franz Wall/r0 unit/z,

May 3, 1938; WEITKOWITZ 2,116,293

DEVICE ADAFTED TO LOUDSIEAKERS, TELEPHONES, OR RELAYS Filed July 11, 1953 2 Sheets-Sheet 2 Eg Z In ventor: v

f Franz W zzlrowyfiz,

HIS Ma /6 Patented May 3, 1938 PATENT OFFICE DEVICE ADAPTED TO LOUDSPEAKERS, TELEPHONES, QR RELAYS Franz Weitkowitz, ()stei'ode, Germany Application July 11, 1933, Serial No. 679,948

' In Germany July 13, 1932 8 Claims.

My invention relates to a device adapted to loud-speakers, telephones or relays, by means of 'which alternating currents e. g. vocal currents cause a membrane or the like to vibrate.

, According to the invention an armature made of aluminium, copper sheet or the like is mounted in a magnetic alternating field in such a manner as to be freely movable or rotatable to and fro, whereby the currents producing the' vibrations m are induced in the armature by alternate magnetic fields. The armature can be made very light, a factor which is extremely important for the undistorted transmission of vocal vibrations.

Several forms of the invention are shown dia- 15 grammatically in the accompanying drawings, in

which Figure 1 is a view, in side elevation, of a twin speaker constituting a preferred embodiment of my invention, the two cones thereof being shown in section.

Fig. 2 is a plan view of the under side of the motor of the device illustrated in Fig. 1, the cones being depicted in cross section:

Fig. 3 is a. view, in side elevation, of another embodiment of my invention in which a single a pair of coacting voice coils;

Fig. 4 is a view, partly in side elevation and partly in cross section, of another embodiment of my invention in which a single voice coil and single diaphragm is employed;

Fig. 5 is a view, primarily in side elevation, of another embodiment of my generic concept, in which two coacting magnet systems having a 35 common voice coil with two poles are'employed to influence a single-diaphragm-driving armature;

Fig. 6 is a view, in side elevation, of a device generally similar to that illustrated in Fig. 5,-but provided with a curvilinear armature associated with complementarily curved pole faces; and

Fig. 7 is a perspective view of a built-up armature especially adapted for devices of the type above set forth, said armature consisting of a 45 plurality of metallic wirewindings pressed into sheet form.

In the example shown in Fig. 1 in elevation and in Fig. 2 in ground plan (seen from below in section 2-2 of Fig. 1) a is a permanent magnet,

50 a, a are laminated pole-shoes, c is a fixed coil through which the alternating current or the vocal current passes, d is the fixed laminated iron core of the coil 0, the central axis of the core (1 lying between the poles'N and S of the pole- 55 shoes a, a of the permanent magnet a; i is.

cone is driven by a vane subject to influence by the air gap between the front surface of the core d and the pole-shoes a, a. In this gap there can be shifted freely to and fro a metal plate f preferably consisting of an aluminium or copper. sheet and connected on each side by a rod g with a membrane b. The metal plate I may have the form of a rectangle extending on all sides beyond the end surfaces of the poles N and S.

If an alternating current, e. g. a vocal current, is sent through the coil 0, the armature ,f is moved to and fro in the rhythm of the currents alternately in the direction from N to S, and from S to N, transmitting its vibrations to the membranes b, b. The armature ,f is meanwhile held by the connecting rods in such a manner, that it cannot touch either the core d or the poleshoes a, a. e is a bed plate, 6'', e are pedestals, upon which the whole device is mounted.

Instead of a permanent magnet a, an electromagnet or several permanent magnets or several electromagnets may be used.

In the example shown in Fig. 3 the armature f has the form of a part of a hollow cylinder and can rotate about or oscillate about the axis h. a is a permanent magnet or electromagnet. The laminated pole-shoes a, a are hollowed out cylindrically to correspond to the form of the armature 1. At either side of the armature f a fixed coil 0 is mounted. The alternating currents or the vocal currents pass through both coils c.

d, d are fixed laminated cores of the coils c, c, the cores d, (1 being separated from each other by an air gap 1'. The two sides ,1, J of the hollow cylindrical metal sector are connected with each other at their two ends by metallic plates. The head pieces of the iron cores d, d are shaped to correspond to the form of the armature I, so that a second air gap k is left between the pole-shoes a, a and the saidhead pieces of the cores .d, d.

In this air gap the armature ,f is rotatably or oscillatably inserted. N and S constitute respectively the north pole and the south pole. 0n the axis h of the armature f is fixed a lever y connected with the membrane d by a rod Z.

In the example shown in Fig. 4, a permanent 5 magnet a, the poles of which are disposed one above the other, and the laminated core d of the coil 0 through which the alternating or vocal currents flow, are rigidly mounted on a'bedplate e. In the air gap between the core d and the poles N, S, of the permanent magnet a, is suspended perpendicularly the metal plate I, consisting of thin aluminium or copper sheet or the like and connected by a rod g with the membrane b.

In the example shown in Fig. 5, two permanent magnets a, a are fixed on the bedplate e in such a manner that the poles Nand. S of the one lie opposite the poles S and N respectively of the other. Between these two pairs of poles is placed the core d, also attached to the bedplate e by means of the supports it. Both in the air gap between the magnet a. on the left hand and the left front face of. the core (1 and in the air gap between the right-hand magnet a and the right front face of the core d is suspended a metal plate f moving freely up and down. The two metal plates f,' f consist of thin aluminium or copper sheet or the like and are connected with each other and with the membrane by a forked rod g.

in the example shown in Fig. 6, two permanent magnets a, a are fixed on the bedplate e in such a manner that the poles N and N of the one and the other magnet, and the poles S and S of the one and the other magnet directly face each other. Between the cylindrically shaped outer surfaces of the core d and the coaxially hollowed out opposing front faces of the magnets a, a are mounted the cylindrical metal plates 1, f, consisting of thin aluminium or copper sheet or'the like and oscillating about an axis 71.. The two metal plates f, j are connected with each other at their two ends by metallic plates. On the axis h is fixed a lever 9 connected with the membrane b bya rod Z.

All the examples of the invention shown in the figures and described in the specification have the following advantages in common: simplicity of construction, light weight of the armature consisting of thin metal sheet of small dimensions, extreme narrowness of the air-gap due to the fact that the armature consisting of a thin straight or curved metal plate shifts only in its own plane or cylindrical surface respectively, great intensity of the magnetic field due to the narrowness of the air gap, possibility to reduce the intensity of the soundby increasing the air gap.

The armatures f may, instead of a continuous sheet, consist of metallic wire windings pressed into sheet form( as illustrated in Fig. '7. Such a fabricated armature element may be flat or curved in form, depending upon the shape of the pole pieces with which it is to be associated.

For instance, as shown in Fig. 7, the armature consists of separate wire loops f which may be connected with each other by an agglutinant. In this figure the armature is shown as a fiat body although it may be other forms, such as the shape of the armatures shown in Figs. 3 and 6.

What I claim is:

1. In a mechanism for translating alternating currents into mechanical vibrations of a body, a magnetic circuit including a pair of closely spaced, opposed pole elements disposed side-byside defining a bi-polar face, a second, independently energized magnetic circuit having a single,

pole element the face of which spans both poles of said bi-polar face in fixed, closely spaced relation thereto, a fixed winding disposed about one of said magnetic circuits for energizing said circuit in accordance with the alternating current to be translated, said other magnetic circuit being characterized by the presence therein of a. constant, field, and an armature comprising a vane of electrically conductive material supported for vibratory movement in the space defined by said bi-polar and complementary uni-polar faces.

2. In a mechanism for translating alternating currents into mechanical vibrations of a body, a magnet having constantly polarized north and south pole termini disposed in closely adjacent, side-by-side relation presenting a bi-polar face, a second magnet having a single pole face complementary to said bi-polar face and disposed in closely-spaced, fixed relation thereto spanning both north and south poles thereof, a stationary winding disposed about said second magnet for energizing the uni-polar face thereof in accordance with the alternating current to be translated, and an armature comprising a vane of electrically conductive material supported for vibratory movement in the space defined by said bi-polar and complementary uni-polar magnet faces.

3. In a mechanism for translating alternating currents into mechanical vibrations of a body, a magnet having constantly polarized north and south poles disposed in closely adjacent side-byside relation presenting a bi-polar face, a distinct electromagnet having a single pole of its core extending spacedly across said bi-polar face in close proximity thereto, complementarily overlying and spanning both the north and the south poles of said first magnet, said electromagnet having an energizing winding upon its core adapted for connection to the alternating current to be translated, and an armature including a vane of electrically conductive material disposed between said bi-polar face and the complementary uni-polar face of said electromagnet and supported for vibratory movement within the space jointly defined by said three po-le faces.

4. In a mechanism for translating alternating currents into mechanical vibrations of a body, a magnetic circuit including a pair of closely spaced opposed pole elements disposed side by side and defining an arcuate bi-polar face, a second, independently energized magnetic circuit having a uni-polar element which is complementary to and spans said areuate bi-polar face in closely spaced, bridging relation thereto, a winding for energizing one of said magnetic circuits in accordance with the alternating current to be translated, said other magnetic circuit being characterized by the presence therein of an independently maintained constant field, and an armature including a curved, electrically-conductive vane supported for vibratory movement in the arcuate space defined by said bi-polar and complementary uni-polar faces.

5. In a mechanism for translating alternating currents into mechanical vibrations of a body, a magnetic circuit including a pair of closely spaced, opposed pole elements disposed side by side defining a bi-polar face, a second, independently energized magnetic circuit having, a single pole element the face of which is complementary in shape to said bi-polar face and spans both magnetic circuit including a pair of closely spaced, opposed pole elements disposed side-hyside defining a bi-polar face, a second, independently energized magnetic circuit having a single pole element the face oi which spans both poles of said bi-polar iaee in fixed, closely spaced relation thereto, a fixed winding disposed about one of said magnetic circuits for energizing said cir-' cult in accordance with the alternating current to be translated, said other ma netic circuit being cbaracterised'by the presencetherein 01' a constant field, and an armature comprising a vane oi electrically conductive material supported for vibratory movement in the space defined by said bi-polar and complementary uni-polar faces, said vane having alateral spread such as to extend beyond the margins oi. said uni-polar face.

I. In a mechanism for translating alternating currents into mechanical vibrations ot a body, a

magneticcircuitincludingapairoiclosely 'spaced,'opposed pole elements flatly disposed side-by-side defining a hi-polar face,-a second,

independentLv-energiled magnetic circuit havins a single poleelement the face 0! which clmely spans said hi-polar face in fixed. uniiornrly spaced relation thereto, a fixed winding about one of said'magnetic circuits for energising said circuit in accordance with the alternating current tobetranslated.ssidothercircuitbeingcharacterisedbythepresencethereinoiaconstant Mandanarmatuncompdlnaafiatvaneot electrically conductive material supported for vihratorymovementinthespacedefinedhysaid bi-polar and commentary uni-polar hoes.

8.1nameehanismiortransiatingaiternating currents into mechanical vibrations of a body, a constantly energisedrnagnetic circuitineiuding apairofcloaelyspacedopposedpoleelements disposed side-hy-side defining a bi-polar face, a variablyeneraisedmslnetiecircuitonepoleiace oi whichspansboth poles otsaidhi-polartaoein fixed. closely spaced relation thereto, a second constantlyenergisedmaaneticcircuitsimilarto thefirstandhavinaapairotclo'aelyspaced.opposed pole elements disposed side-by-side defin- 'ingaseeondbi-polariaee spannedbytheother pole'taceoisaidvariabiyeneraisedmagneticcircuit fixed w'indingdispoaedahoutsaid variably magneticcircuittoenergiseeaehpole thereotinaecordsneewiththealternatingcur rer'ittobetranslated,andanarmaturehaving vaneportimsofelectricallyconductivematerial respectively supported for vibratory movement in the spaces defined polarandbi-poiariaoe.

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